Interisland ocean shipper Young Bros. Ltd. said it will raise rates for all shipments by 5.5 percent starting today, following yesterday's approval by the state Public Utilities Commission. It is the company's fourth rate increase in four years.

The decision finalizes a request made June 18 by Young Brothers to raise rates across the board to help pay for a 10-year, $186 million plan to improve its equipment and infrastructure.

The increase was announced on the same day Matson Navigation Co. said it will raise its fuel surcharge for its Hawaii, Guam and Micronesia service by 4 percentage points starting Aug. 31. It will be the fourth increase this year for the state's largest ocean shipper.

Young Brothers raised its fuel surcharge in June to 4.22 percent from a 2.78 percent fee set in March. The fuel surcharge, implemented late last year, covers just more than a third of increased fuel costs, said spokesman Roy Catalani. The company will implement another fuel-price adjustment on Sept. 1, but Catalani said that rate hasn't been decided yet.

The company said it expects to raise $3.5 million in additional annual revenue from today's increase for the upgrades, including adding four larger barges as well as upgrading facilities in Honolulu, Kawaihae and Kahului. Young Brothers is likely to file another rate case with the PUC in 2009, Catalani said.

Young Brothers last raised rates by 7.51 percent in fall 2007. The company may request a rate increase once a year and adjust for fuel prices each quarter.

With the increase, shipping 2,000 pounds of refrigerated isle cabbage will cost about $63, while 40 cubic feet of canned goods, or 1,920 soup cans, would cost $31.